An important prerequisite for correct regulation of the operation of such an internal combustion engine is its synchronization. For this purpose the angles of rotation of the crankshaft and the camshaft are generally monitored using a crankshaft sensor with an assigned toothed pickup wheel and a camshaft sensor with an assigned pickup wheel, in order to determine the angle position of the internal combustion engine from these. GB 2,065,310; EP 0 310 823; WO 89 04 426 and U.S. Pat. No. 4,766,359 also disclose such combustion engines.
Much effort has been made to minimize the startup time required to start the internal combustion engine. One design used for this purpose is a specifically configured camshaft pickup wheel (“fast start camshaft”), which has a number of asymmetrically configured toothed rims. Using a specifically configured camshaft pickup wheel is however complex and expensive.
Another option for determining the initial angle position of the internal combustion engine makes use of the fact that an internal combustion engine always remains in specific discrete angle positions after being switching off when the clutch is disengaged. This fact is used in conjunction with the signals from conventional crankshaft and camshaft sensors to estimate the initial angle position of the internal combustion engine when the engine restarts. However, the accuracy of this method is limited, as it determines a more or less broad angle position range, not the precise angle position of the internal combustion engine. Additionally, errors in the determination of the initial angle position are unavoidable, if the internal combustion engine is operated after being switched off with the clutch engaged, as may be the case when parking the associated vehicle on a slope.